The negative impact of infestation by pests on agricultural production is well-known. Damage worldwide due to nematode infestation alone is estimated at $78 billion per year. Other sources of infestation include bacterial, fungal, and insect pathogens. Assault on these infestations has taken the form of use of synthetic pesticides derived from petroleum, use of natural predators, and use of compounds derived from natural sources, such a pyrethrins. No completely satisfactory pesticide which is specific, effective, and not harmful to the environment has been found. Thus, there is a considerable need for finding improved pesticides.
With regard to previous compositions related to those of the present invention, the effect of fatty acids on a particular species of plant nematodes (Meloidogyne javanica) has been described by-Sitaramaiah, K., et al., Indian J. Nematol. (1977) 7:58-65. Formic, acetic, propionic and butyric acids were tested. The effect of a collagenolytic/proteolytic enzyme secreted from Bacillus cereus after induction by collagen on this plant nematode species has also been reported by Sela, S., et al., Eur. J. Plant Pathol. (1998)104:59-67. The enzyme was effective to digest collagen from cuticles of second stage juveniles. U.S. Pat. No. 5,698,592 describes compositions for the control of plant infective nematodes using fatty acid compounds which compositions are microemulsions containing C8-C14 fatty acid esters. The esters were prepared synthetically and the nature of the microemulsions is not described.
Fatty acid or oil compositions have also been described for other purposes, including the use of a vegetable oil/mineral salt broth fermented by yeast as an emulsifier in the food industry, as described in U.S. Pat. No. 4,810,507; the use of a mixture of an oleate derivative, a lower alkanol, and an inert diluent as a pharmaceutical penetration agent, as described in U.S. Pat. No. 4,863,970; and the use of a solution of oleic acid, acetone, and ammonium hydroxide in water as a treatment for athlete's foot, as described in U.S. Pat. No. 4,172,888. Unsaturated lipid compounds containing polar head groups, including oleates, are described as cell-envelope disordering compounds.
The use of microbial infection to control nematode infestation in plants was described in U.S. Pat. No. 5,264,210. PCT Application WO98/59036 describes compositions for the control of nematode infestation using metabolites from fungi. In some cases, the fungi are cultured in media which include vegetable oil and the compositions may include surfactants.
U.S. Pat. Nos. 5,674,897; 5,698,592; and 6,124,359, all assigned to Mycogen describe microemulsions containing fatty acid esters for use as nematocides. These fatty acid esters are of C8-C14 fatty acids and they do not appear to include glyceride esters. Various other patents disclose the use of alkoxylated materials and other emulsifiers for use in pesticides or herbicides intended for application to plants. These include U.S. Pat. Nos. 4,975,110 and 5,098,467 to Safer; U.S. Pat. No. 5,827,522 to Troy and U.S. Pat. No. 6,093,681 to Monsanto. In addition, U.S. Pat. No. 5,362,707 assigned to Rhone Poulenc describes the use of “suspoemulsions” as vehicles to apply pesticides with solid active ingredients (having melting points >45° C.) to plants.
It has not heretofore been appreciated that complexes containing a hydrophilic core, at least one monounsaturated fatty acid backbone, surfactants, and including a polyalkoxylene, (such as compositions containing a denatured lipase with long chain fatty acids or their derivatives) prepared in the form of a clear microemulsion are particularly effective in controlling pests in agricultural settings.
In addition, the formulation of agents employed for dispersal and penetration of active ingredients is useful as a carrier for plant nutrients, pesticides in general, herbicides, and other materials suitable for application to plants and is also useful as a topical drug delivery system.
A wide variety of carriers for active ingredients has been devised in both the pharmaceutical and agricultural arts. For example, drug delivery systems have included various forms of liposomes, various polymeric slow-release compositions, detergents which aid in penetration, and other excipients that affect the behavior of small molecules or proteins or other biological molecules that are considered to be the active ingredients. The formulation of the present invention, originally developed as a carrier for nematocides, has been found useful as a delivery system for pesticides in general, for plant nutrients, and for topical application of drugs as well. The carrier of the present invention is particularly effective in dispersing active ingredients over a wide area and in effecting penetration of these active ingredients through cell walls and membranes and is thus useful both in agricultural and pharmaceutical contexts.